Statistics for occurrence #1 of “Portsmouth” in entry chesapeake of Harper's Encyclopedia of United States History:

...ery small sum, who broke her up and sold her timbers for building purposes, much of it for making houses in Portsmouth, and a considerable portion for the erection of a mill at Wickham, 9 miles from Portsmouth .
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Portsmouth (New Hampshire, United States) 470 225 134 39 0 user votes
Portsmouth (United Kingdom) 107 15 13 5 0 user votes
Portsmouth (Dominica) 0 0 0 0 0 user votes
Portsmouth (Iowa, United States) 0 0 0 0 0 user votes
Portsmouth (Kentucky, United States) 0 0 0 0 0 user votes
Portsmouth (Virginia, United States) 0 0 0 0 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.